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The prokaryotic selenoproteome
Gregory V Kryukov1, Vadim N Gladyshev
1Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664, USA.
EMBO Reports
|April 24, 2004
Summary
This study resolves the dual-function UGA codon problem in prokaryotes by identifying selenoproteins using bioinformatics. This improves gene annotation accuracy for selenoprotein genes and aids in understanding selenoprotein evolution.
Area of Science:
- Genomics
- Molecular Biology
- Bioinformatics
Background:
- The UGA codon in the genetic code has a dual function, encoding selenocysteine (Sec) and acting as a stop signal.
- Current gene annotation programs misinterpret UGA solely as a stop signal, leading to inaccurate selenoprotein gene identification.
Purpose of the Study:
- To characterize the selenoprotein set in prokaryotic genomes.
- To address the misannotation of selenoprotein genes caused by the dual-function UGA codon.
Main Methods:
- Utilized two independent bioinformatics approaches: identification of RNA stem-loop structures and selenocysteine insertion sequence elements, and identification of Sec/Cys pairs in homologous sequences.
- Applied these methods to analyze completely sequenced bacterial and archaeal genomes.
Main Results:
- Successfully identified all or nearly all selenoproteins in prokaryotic genomes.
- Provided a comprehensive view of the distribution and composition of prokaryotic selenoproteomes.
- Detected both lineage-specific and core selenoproteins, offering insights into their evolution.
Conclusions:
- Characterization of prokaryotic selenoproteomes enables accurate interpretation of UGA codons as terminators.
- This work resolves the UGA dual-function problem in prokaryotic genome annotation.
- The findings contribute to understanding selenoprotein evolution and distribution.